1. Field
Apparatuses consistent with exemplary embodiments relate to an image sensor having improved light utilization efficiency.
2. Description of the Related Art
Color display apparatuses and color image sensors generally use color filters in order to display color images or to detect colors in incident light. Color display apparatuses and color image sensors currently in use typically employ a red, green and blue (RGB) color filter in which two of each set of four pixels include green filters and the other two pixels include a blue filter and a red filter. Alternately, a cyan, yellow, green and magenta (CYGM) color filter may be employed in which each set of four pixels includes a cyan filter, a yellow filter, a green filter, and a magenta filter.
However, since conventional absorption-type color filters absorb light of those colors that are not transmitted, the light utilization efficiency of these filters is poor. For example, if RGB color filters are used, at most, a third of any incident light is transmitted through the RGB color filters, and at least two-thirds of the incident light is absorbed. Thus, the light utilization efficiency is, at most, about 33%. Therefore, in the case of a color display apparatus or a color image sensor, most optical losses occur in the color filters.
As the number of pixels of image sensors sensor are increased, widths of the pixels are decreased, and the amount of light reaching any one pixel is decreased. Therefore, it is increasingly important to improve the light utilization efficiency.
Recently, attempts have been made to use color separation elements to improve the light utilization efficiency of color display apparatuses and color image sensors. A color separation element separates incident light according to wavelength by transmitting or diffracting or refracting the incident light according to the wavelength thereof. In this way, light of a particular color may be transmitted to the corresponding pixel, thereby increasing efficiency and color output.